SkyEye

Welcome to SkyEye, your guide to this month's celestial events.

August 2009

All times and dates are given in Universal Time (UT).
Nightly darkness estimates are calculated for 45° N and 30° S.
Like total solar eclipses, lunar occultation events can be seen only from limited regions on Earth (and sometimes not at all if the occultation takes place during daylight hours). However, the Moon will appear close in the sky to its "target" for some hours either side of the actual occultation, regardless of where you are.

Date		Event
1	Sat
2	Sun
3	Mon
4	Tue	Moon at apogee
5	Wed
6	Thu	Full Moon
6	Thu	Like the event last month, this penumbral lunar eclipse cannot be detected by the unaided eye.
7	Fri
8	Sat
9	Sun
10	Mon	Sun passes through the ring plane of Saturn
11	Tue
12	Wed	Moonlight washes out the famous Perseids.
13	Thu	Last Quarter Moon
14	Fri	Moon occults the Pleiades: visible from about 0730 in most of North America (except northwestern part), Mexico, northern Central America and the Bahamas.
14	Fri	Jupiter at opposition
15	Sat
16	Sun
17	Mon	Neptune at opposition
18	Tue
19	Wed	Moon at perigee
20	Thu	New Moon
21	Fri
22	Sat
23	Sun
24	Mon	Mercury at greatest elongation east
25	Tue
26	Wed
27	Thu	First Quarter Moon occults Antares: visible from about 2200 UT in the northern Brazil and northwest Africa.
28	Fri
29	Sat
30	Sun
31	Mon	Moon at apogee

The Solar System

The word planet is derived from the Greek word for "wanderer." Unlike the background stars, planets seem to move around the sky, keeping mostly to a narrow track called the ecliptic, the path of the Sun across the stars. Dwarf planets and small solar-system bodies including comets, are not so constrained, often moving far above or below the ecliptic.

Sun: Cancer -> Leo
Mercury: Leo -> Virgo
Always low in the west after sunset for northern viewers, this tiny planet climbs high above the horizon when observed from southern latitudes, reaching greatest elongation east on 24 August. It passes close by the first-magnitude star Regulus early in the month.
Venus: Orion -> Gemini -> Cancer
Lingering high in the dawn sky as seen from the northern hemisphere, the "morning star" is rapidly losing altitude above the eastern horizon for southern latitudes.
Mars: Taurus -> Gemini
The red planet passes between the "horns" of the bull Taurus mid-month. It rises about midnight.
Jupiter: Capricornus
At opposition on 14 August, the largest planet in the solar system is shining at a brilliant -3 magnitude. It is up all night.
Saturn: Leo
On 10 August the Sun passes through the ring plane. Between this date and 4 September (when Earth passes through the ring plane), the "dark side" of the rings will be facing toward us. However, this will be difficult to observe as Saturn sets shortly after the Sun.
Uranus: Pisces
With opposition approaching next month, Uranus is up nearly all night. It rises as Saturn sets.
Neptune: Capricornus
A small telescope is necessary to view the most distant planet in the solar system. Neptune is at opposition on 17 August but is eighth magnitude at best.

The Celestial Sphere

Constellations are patterns of stars in the sky. The International Astronomical Union (IAU) recognises 88 different constellations. The brightest stars as seen from the Earth are easy to spot but do you know their proper names? With a set of binoculars you can look for fainter objects such as nebulae and galaxies or some of the closest stars to the Sun.

Descriptions of the sky for observers in both the northern and southern hemispheres are available for the following times this month. Subtract one hour from your local time if summer (daylight savings) time is in effect.

Local Time	Northern Hemisphere	Southern Hemisphere
1730 hours (1830 hours summer time)	45° N	30° S
1930 hours (2030 hours summer time)	45° N	30° S
2130 hours (2230 hours summer time)	45° N	30° S
2330 hours (0030 hours summer time)	45° N	30° S
0130 hours (0230 hours summer time)	45° N	30° S
0330 hours (0430 hours summer time)	45° N	30° S
0530 hours (0630 hours summer time)	45° N	30° S

For More Information...

Consult our online glossary for non-technical explanations of many of the astronomical terms used in these pages.
Blue moons, eclipses, the dates of Easter and much more can be found at the Interactive Astronomy Pages.
For more information about the objects and events described in SkyEye, visit these astronomy-related sites.

Credits

Much of this information can be found in this month's issue of your favourite amateur astronomy magazine available in your local bookshop. Another excellent source is the current edition of the Astronomical Calendar by Guy Ottewell and published by the Universal Workshop at Furman University.

The SkyEye banner features a view of Saturn from its satellite Iapetus and is courtesy of NASA/JPL/Space Science Institute. Of all the major satellites of Saturn, Iapetus is the only one with a significant orbital inclination. Thus, whilst the rings appear nearly edge-on from all of the other major satellites, from Iapetus they are usually seen at a tilt. This image was taken during the Cassini-Huygens mission on 10 September 2007 and consists of 15 red, green and blue spectral filter images.